To provide cellular wireless communication service, a wireless service provider typically employs an access network that functions to connect one or more access terminals (e.g., cell phones, PDAs, laptops, netbooks, tablets, and/or other wirelessly-equipped devices) with one or more transport networks. In a typical access network, an area is divided geographically into a number of coverage areas, such as cells and sectors, each defined by a radio frequency (RF) radiation pattern from a respective base transceiver station (BTS). Within each coverage area, the BTS's RF radiation pattern may provide one or more wireless links, each on a carrier (or set of carriers), over which access terminals may communicate with the access network. In turn, the access network may provide connectivity with the public switched telephone network (PSTN), the Internet, and/or other transport networks.
The wireless links may carry communications between the access network and the access terminals according to any of a variety of wireless protocols. Depending on the protocol employed, each wireless link may also be divided into a plurality of channels for carrying communications between the access network and the access terminals. For example, each wireless link may include a plurality of forward-link channels, such as forward traffic channels, for carrying communications from the access network to the access terminals. As another example, each wireless link may include a plurality of reverse-link channels, such as reverse traffic channels, for carrying communications from the access terminals to the access network.
In many wireless protocols, while the access network and an access terminal are engaging in a communication session on a single wireless link, the access network and active access terminals may engage in default power-control processes to control transmission power on the wireless link for the communication session. In particular, the access network and the active access terminal may engage in a default reverse power-control process to control the reverse transmission power at which the access terminal sends bearer data for the communication session on an established reverse traffic channel of the wireless link. Similarly, the access terminal and the access network may engage in a default forward power-control process to control the forward transmission power at which the access network sends bearer data for the communication session on an established forward traffic channel of the wireless link.
In an example default power-control process, a power-controlling entity may send a series of power control commands (PCCs) directed to a power-controlled entity on the wireless link, each of which instructs the power-controlled entity to adjust its transmission power on the wireless link for the communication session. To facilitate sending each such PCC, the power-controlling entity may determine a channel quality at which the wireless link is carrying the communication session and compare the determined channel-quality to a threshold channel-quality. Based on that comparison, the power-controlling entity may decide to send either a “power up” PCC that instructs the power-controlled entity to increase its transmission power on the wireless link for the communication session (if the determined channel-quality is less than the threshold channel-quality) or a “power down” PCC that instructs the power-controlled entity to decrease its transmission power on the wireless link for the communication session (if the determined channel-quality is greater than the threshold channel-quality).
As the power-controlling entity sends the series of PCCs directed to the power-controlled entity, the power-controlled entity may receive PCCs from the series of PCCs sent by the power-controlling entity. As it receives these PCCs, the power-controlled entity may responsively adjust its transmission power for the communication session on the wireless link. For instance, in response to receiving a “power up” PCC from the power-controlling entity, the power-controlled entity may increase its transmission power for the communication session on the wireless link. And in response to receiving a “power down” PCC from the power-controlling entity the power-controlled entity may decrease its transmission power for the communication session on the wireless link.
Advantageously, such a default power-control process may enable the access network and active access terminals to balance between maintaining an acceptable strength of a traffic-channel communication and preventing the traffic-channel communication from becoming overly strong and unduly interfering with other communications.